Normally, a solar panel, such as a thin film solar panel is formed by monolithically inter-connected cells using mechanical/laser scribing. FIG. 1 illustrates a conventional laser-scribing process for a CIGS solar module in the prior art. As shown in FIG. 1, there are totally three scribing lines, i.e., P1, P2 and P3 lines. Firstly, a Mo film is isolated by laser-scribing into equally spaced strips which have a width of 5 mm. The width of P1 line is about 20-70 μm. Then, a CIGS absorption layer, CdS and i-ZnO films are deposited on the Mo film. Additional P2 line is scribed right next to the P1 line to get rid of CIGS, CdS and i-ZnO films. The width of the P2 line is about 30-100 nm, depending on the scribing condition. Deposition of AZO front contact leads to inter-connection of front contact of the cell on the left to the back contact of the cell on the right side of P2 line. A P3 line with a width similar to that of P2 line is used to isolate the front contact connections among different cell strips. The cell strips are inter-connected into a whole module. The area from P1 to P3 lines is called dead area because of the wasted solar radiation. If P2 and P3 lines are scribed mechanically, the whole dead area is commonly about 0.2-0.3 mm; and if they are scribed by using laser-scribing techniques, the whole dead area may be reduced to less than 0.2 mm (0.14-0.2 mm). However, the P1, P2 and P3 lines are usually simple straight lines separated side by side in the prior art, which cannot satisfy the market requirements for product customization.
In addition, for the thin film solar panel on a flexible substrate, such as polyimide, it is very difficult to scribe patterns by using conventional laser-scribing techniques. Because even if the P1 line on a Mo back contact layer is straight at first, it will bend in the followed processes since the substrate may suffer from the thermal distortion. Then, if the P2 line will be scribed next to the bent P1, a crossover will easily occur. The same situations will also arise for the P2 and P3 lines. Therefore, the yield and the total power efficiency of the solar panel are greatly reduced.
There is therefore a need for a practical approach to address at least one of the above mentioned problems.